Vitamin D deficiency (VDD) has prevalence as high as 92 % in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD) and it has been associated with decreased muscle strength, anemia, resistance to treatment with recombinant human erythropoietin (EPO) and increased mortality in these patients [1–6]. This evidence concerns the gene EPO and anemia (phenotype).